Re: [PATCH net v9 01/14] afs: Fix lack of loop around sendmsg() to rxrpc

[David Laight]

On Mon,  7 Sep 2026 12:37:28 +0100
David Howells <dhowells@xxxxxxxxxx> wrote:

> Fix the afs callers of sendmsg() to send data through an rxrpc socket to
> call again if a short send occurs.
> 
> Note that this is also a prerequisite for changing the way rxrpc_send_data()
> works to return a short send rather than an error if some data was buffered.
> 
> Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.")
> Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
> cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> cc: Simon Horman <horms@xxxxxxxxxx>
> cc: linux-afs@xxxxxxxxxxxxxxxxxxx
> cc: stable@xxxxxxxxxxxxxxx
> ---
>  fs/afs/rxrpc.c | 38 ++++++++++++++++++++++++--------------
>  1 file changed, 24 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
> index d82916657a3d..a80b043d36be 100644
> --- a/fs/afs/rxrpc.c
> +++ b/fs/afs/rxrpc.c
> @@ -412,26 +412,32 @@ void afs_make_call(struct afs_call *call, gfp_t gfp)
>  	msg.msg_controllen	= 0;
>  	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
>  
> -	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
> -				     &msg, call->request_size,
> -				     afs_notify_end_request_tx);
> -	if (ret < 0)
> -		goto error_do_abort;
> +	do {
> +		ret = rxrpc_kernel_send_data(call->net->socket, rxcall, &msg,
> +					     msg_data_left(&msg),
> +					     afs_notify_end_request_tx);
> +		if (ret < 0)
> +			goto error_do_abort;
> +	} while (msg_data_left(&msg) > 0);

Is there any reason you didn't change rxrpc_kernel_send_data() instead?

David

>  
>  	if (call->write_iter) {
>  		msg.msg_iter = *call->write_iter;
>  		msg.msg_flags &= ~MSG_MORE;
>  		trace_afs_send_data(call, &msg);
>  
> -		ret = rxrpc_kernel_send_data(call->net->socket,
> -					     call->rxcall, &msg,
> -					     iov_iter_count(&msg.msg_iter),
> -					     afs_notify_end_request_tx);
> +		do {
> +			ret = rxrpc_kernel_send_data(call->net->socket,
> +						     call->rxcall, &msg,
> +						     msg_data_left(&msg),
> +						     afs_notify_end_request_tx);
> +			if (ret < 0) {
> +				trace_afs_sent_data(call, &msg, ret);
> +				goto error_do_abort;
> +			}
> +		} while (msg_data_left(&msg) > 0);
>  		*call->write_iter = msg.msg_iter;
>  
> -		trace_afs_sent_data(call, &msg, ret);
> -		if (ret < 0)
> -			goto error_do_abort;
> +		trace_afs_sent_data(call, &msg, 0);
>  	}
>  
>  	/* Note that at this point, we may have received the reply or an abort
> @@ -912,8 +918,12 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
>  	msg.msg_controllen	= 0;
>  	msg.msg_flags		= 0;
>  
> -	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
> -				   afs_notify_end_reply_tx);
> +	do {
> +		n = rxrpc_kernel_send_data(net->socket, call->rxcall,
> +					   &msg, msg_data_left(&msg),
> +					   afs_notify_end_reply_tx);
> +	} while (n >= 0 && msg_data_left(&msg) > 0);
> +
>  	if (n >= 0) {
>  		/* Success */
>  		_leave(" [replied]");
> 
>